This invention relates to a hydraulic coupling device for a multi-line hose. The invention is useful in the hydraulic distribution systems used in underground mine workings, particularly for hydraulic advanceable mine roof support assemblies and other hydraulic appliances.
Systems are known in which numerous hydraulic lines are bunched together to form multi-line hoses, which are interconnected by means of generally cylindrical plug couplings. A known plug coupling includes a coupling device having a plurality of plug pins, and a connector having a plurality of sockets which mate with the plug pins, the coupling device and the connector being attached to respective multi-line hoses.
Such a coupling device has a casing which houses the plug pins, the plug pins being supported by a holder within the casing. Each of the plug pins is attached to the holder in such a manner as to permit a slight amount of axial and radial play so that the plug pins can easily be positioned within the sockets of the connector, without forcing or deformation. The holder is a disc provided with apertures for receiving the plug pins, the apertures lying on a common pitch circle.
A known coupling device of this type has a nut which houses the plug pins. The nut is connected to the associated multi-line hose by means of a sleeve. Each of the plug pins has a collar, the collars being braced against an apertured holding disc by abutment faces formed on a retaining disc and on the end of the sleeve. The two discs are connected by means of a central screw to form a composite plate which is held in the nut between an inwardly-extending flange formed within the nut and an annular flange provided at the end of the sleeve. The holding disc is provided with apertures for receiving the plug pins, each aperture having a diameter which is less than that of the collar of the associated plug pin.
The holding and retaining discs of this type of coupling device have different diameters and thicknesses, and both discs are of stepped formation. The retaining disc has a central cylindrical projection which engages within a central circular recess in the holding disc. This disc arrangement, and the provision of the abutment face on the sleeve for bracing the collars of the plug pins, involves a relatively high production cost which greatly increases the price of mass-produced coupling devices of this type. Moreover, the two discs are relatively thick, so that a relatively great weight is involved in the handling of the coupling device. This is particularly the case where the discs (and therefore the entire coupling device) must be of relatively large diameter to accommodate a multi-line hose having a fairly large number of lines, since the plug pins can be positioned only along a common pitch circle. This is because the central zone of the holding disc, which is surrounded by the pitch circle, cannot be used for positioning any of the plug pins, since the connecting screw for the two discs is located here.
The aim of the invention is to provide a coupling device of considerably reduced cost, and which has comparatively small longitudinal and radial dimensions and a comparatively low weight.